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Hi I have the following code which is meant to find the word "is" but not when it is within another string so the word "this" should not return a match so I use \b. But the following code does not find a match and I cant figure out why?
public static void main(String[] args) {
String a = "This island is beautiful.";
Pattern p = Pattern.compile("\bis\b");
Matcher m = p.matcher(a);
while(m.find()){
System.out.println(a.substring(m.start(), m.end()));
}
}
870
Introduction to the Python regex word boundary Before the first character in the string if the first character is a word character ( \w ). Between two characters in the string if the first character is a word character ( \w ) and the other is not ( \W – inverse character set of the word character \w ).
The subexpression/metacharacter “\b” matches the word boundaries when outside the brackets. Matches the backspace (0x08) when inside the brackets.
A word boundary \b is a test, just like ^ and $ . When the regexp engine (program module that implements searching for regexps) comes across \b , it checks that the position in the string is a word boundary.
Double escape it:
Pattern p = Pattern.compile("\\bis\\b");
Regex in Java requires you to doubly escape certain special regex symbols, one escaping for Java and another for underlying regex engine.
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